JP3738859B2

JP3738859B2 - Composition for peeling adhesive of circuit connection part and peeling method using the same

Info

Publication number: JP3738859B2
Application number: JP23796095A
Authority: JP
Inventors: 功塚越; 敦夫中島; 宏治小林; 幸寿廣澤; 美佐夫小口; 寛松岡
Original assignee: Hitachi Chemical Co Ltd; Showa Denko Materials Co Ltd
Current assignee: Showa Denko Materials Co Ltd
Priority date: 1994-11-25
Filing date: 1995-09-18
Publication date: 2006-01-25
Anticipated expiration: 2015-09-18
Also published as: JPH08199191A

Description

【０００１】
【発明の属する技術分野】
本発明は接着剤による回路や電極等の接続部の、補修に好適な剥離用組成物およびそれを用いた剥離方法に関する。
【０００２】
【従来の技術】
電子部品の小型薄型化に伴い、これらに用いる回路や電極等は、高密度、高精細化している。これら微細回路等の接続は、接着剤による方法が最近多用されるようになってきた。この場合、接着剤中に導電性粒子を配合し加圧により接着剤の厚み方向に電気的接続をえるもの（例えば特開昭５５−１０４００７号公報）と、導電性粒子を用いないで接続時の加圧により電極面の微細凹凸により電気的接続をえるもの（例えば特開昭６０−２６２４３０号公報）がある。
【０００３】
これら接着剤による接続において、電気的接続が不良であったり、接続後に電子部品や回路が不良になった場合、接続部間を剥離し、残った接着剤を溶剤や剥離液等で除去した後、再度良品を接着剤により接続することがおこなわれる。この時、例えば液晶デイスプレイパネルのような多数の接続用回路を有する１つの電子部品に、多数の例えばＩＣチップのような他の電子部品を接続する場合、前記の接着剤除去法では、周辺部の他の接続部にまで影響し、接続不良や信頼性が低下する問題があった。
【０００４】
また、最近ではこの様な用途に使用される接着剤は、接続信頼性に優れることから熱や紫外線等による硬化型が多用されるが、その場合の適当な剥離液がなく接続不良や信頼性が低下する問題を抱えながら使用されていた。これらの対策として先に本発明者等は、補修を要する接着剤面積とほぼ等しい所定形状の多孔質シ−トに剥離液を含ませ、補修を要する接着剤と接触させて剥離させる試みを提案した。（特開平３−２８３２８４号）
【０００５】
【発明が解決しようとする課題】
特開平３−２８３２８４号の方法は、限定領域の極めて有効な剥離方法であるが、所定形状の多孔質シ−トを補修が必要な部分のみに形成するため、シ−トの正確な切断や裁置、および剥離液の含浸が必要なことから作業性に欠けるきらいがある。また、剥離液中に酸やハロゲン系溶剤を含む場合に、電食が発生し易く接続信頼性が不十分であった。加えて、ガラスエポキシ基板上の回路を接続するような場合に、剥離を要する接着剤の形成面がこれと同様な接着剤材質の近傍にある場合には、剥離液の程度次第で下地の基板の接着剤や回路と基板の接着剤をも劣化させてしまう欠点があった。
【０００６】
本発明は、上記欠点を解消すべくなされたものであり、補修が必要な部分のみの接着剤を効率良く剥離でき、かつ接続信頼性に優れた剥離用組成物及び剥離方法を提案するものである。
【０００７】
【課題を解決するための手段】
本発明は、沸点が１１０℃以上の１分子中に２個以上のカルボニル基を有するケトン系有機溶剤１００重量部に対し、この溶剤に不溶性の多孔質体微粉０．５〜５０重量部を含有してなる剥離用組成物、および剥離を要する接着剤部に前記組成物を接触させ、暫時接触後にこれらを取り除き清浄化する剥離方法に関する。
【０００８】
【発明の実施の形態】
本発明に用いる有機溶剤について説明すると、接着剤を分解または膨潤、溶解する性質を持つもので、特に硬化後の接着剤を分解または膨潤、溶解し易いものが好ましい。そのため本発明における必須溶剤として、沸点（７６０ｍｍＨｇ）が１１０℃以上の１分子中に２個以上のカルボニル基を有するケトン系有機溶剤が好ましい。この様な溶剤は、例えば（株）講談社発行、溶剤ハンドブック、第７刷、６３２頁〜７５６頁に示されておりこれらを適用できる。本発明は上記のように沸点（７６０ｍｍＨｇ）が１１０℃以上のケトン系有機溶剤をもちいることを必須とするが、所望により沸点が１００℃以下の有機溶剤を適宜配合してもよい。
【０００９】
この溶剤を例示すると、アセトニルアセトン（１９１℃）である。１分子中に２個以上のカルボニル基を有するものが、特に硬化後の接着剤を分解または膨潤しやすく好ましい。これらの沸点は揮発性抑制の点から１１０℃以上が適用可能であり、１２０℃以上が好ましく、１４０℃以上がより好ましい。
【００１０】
剥離液中の溶剤は酸やハロゲン系溶剤を含有しない、非ハロゲン系の有機溶剤であることが、接続信頼性を保持することから必要である。溶剤の粘度は、低い方が剥離すべき接着剤への浸透性がよく好ましい。またＳＰ値は８以上、より好ましくは１０以上が、接着剤の浸蝕作用が大きいので好ましい。本発明に用いる多孔質体微粉は、内部または表面に多数の小さな空隙を有するものであり、剥離用組成物の溶剤に不溶性であることが必要である。剥離用組成物を補修が必要な部分のみに形成するためには適用回路類の精細性の点から、空隙の孔径は１００μｍ以下が好ましく、より好ましくは４０μｍ以下である。空隙の度合いをしめす指標として、本発明おいてはＢＥＴ法比表面積（ＡＳＴＭＤ−３０３７−７３）が、１ｍ^２／ｇ以上のものが好ましく、１０ｍ^２／ｇ以上のものがより好ましく適用できる。
【００１１】
また多孔質体の吸油量（ＪＩＳＫ５１０１）が２０以上であるものも好ましく適用できる。本発明に用いる多孔質体微粉が溶剤に溶解性であると、剥離用組成物の揺変性や溶剤の保持性が低下してしまい好ましくないが、これらの特性が大幅に低下せず実用上問題なければ若干の膨潤程度は差支えない。これら多孔質体微粉を例示すると、炭酸カルシウムやマグネシウムなどの炭酸塩、水酸化アルミニウムやマグネシウムなどの水酸化物、酸化亜鉛やマグネシウムなどの酸化物、シリカやスメクタイト、タルク等のケイ酸及びケイ酸塩、スチレンやエポキシ樹脂などのポリマ粒子類などがある。ポリマ粒子類の場合、溶剤による変質防止のため架橋体が好ましい。また、カ−ボンなどの導電性を有するものも、清浄化工程の摩擦により発生する静電気除去作用があり好ましい。これら粒子類は、添加量を少なくしても揺変性を得られることから微粒子状が好ましく、その粒径は１０μｍ以下、より好ましくは粒径１μｍ以下である。また、架橋ポリマの多孔質シ−ト類や吸水性樹脂類を、粉砕等により微粉化したものも適用可能である。この場合の微粉の大きさは数ｍｍ以下、好ましくは数百μｍ以下と比較的大きなサイズのものまで適用できるので、剥離用組成物中への分散が容易であり、さらに溶剤の保持量を多量とすることが可能となり好ましい。微粉化したものと前記微粒子状の物は混合して用いることも可能である。
【００１２】
以上よりなる組成物を液状に調整して、本発明になる剥離用組成物を得る。液状とする理由は、補修が必要な部分のみに容易に形成容易とするためである。この時、組成物の粘度（ＪＩＳＫ６８３３）は、１００ｃｐｓ以上が好ましく、８００ｃｐｓ以上がより好ましい。粘度の上限は、１００、０００ｃｐｓ程度のペ−スト状までの広い範囲が適用できる。また同法によるチキソトロピックインデックスは、１．２以上が好ましく、１．５以上がより好ましい。粘度が低いと接着剤への浸透性に優れ、チキソトロピックインデックスが大きいと細部への精密な形成性が向上する。これらの理由から多孔質体微粉の添加量は、前記溶剤１００重量部に対し０．５〜５０重量部が適用可能であり、１〜２０重量部がより好ましい。剥離用組成物中には、例えば使用溶剤に可溶な増粘剤としてのポリマ類や、剥離すべき接着剤への溶剤の浸透性を増進する界面活性剤、形成領域を明示するための着色材、などを必要に応じて使用することもできる。
【００１３】
以上よりなる剥離用組成物を用いた剥離方法について説明する。まず補修を要する接続部の相互の接合部を必要に応じて剥離させ、剥離を要する接着剤面を露出させる。この時例えば接着剤のガラス転移点以上に加熱しながら行うと剥離が容易である。補修面積が微小の場合など、接合部に剥離用組成物が簡単に浸入出来る場合、本工程は省略することもできる。次に、剥離を要する接着剤露出面に剥離用組成物を形成し暫時接触させる。形成手段としては、剥離用組成物が液状なので、例えば刷毛、デイスペンサ、シルクスクリ−ン等適宜選択出来る。この時、周辺部への悪影響を防止するためマスキングテ−プ等により、除去しない部分を保護しても良い。接触時間は、接着剤を分解または溶解する時間で決定する。この時高沸点溶剤の揮発を抑制出来る程度に加熱しながら行うと、接着剤を分解または溶解することがさらに容易となり作業時間の短縮に有効である。この後、剥離用組成物の形成面を、布、紙、綿棒等で拭きとるか、これらにアセトンやアルコ−ル等の溶剤を含浸させたもので拭きとる等により、接着剤を取り除き清浄化する。
【００１４】
本発明が適用される接着剤は、硬化剤が触媒硬化型の例えばエポキシ樹脂が主成分であると好適である。すなわち、回路接続用接着剤は短時間硬化が求められることから、開環重合を開始させる触媒硬化型が用いられる。一方、基板や基板と回路との接着剤は重付加型が多用され、これらの硬化物の構造が異なるために耐溶剤性に差を生じる。一般的に触媒硬化型に比べ重付加型は、高度に網状化されないと機械的物性の発現が不十分なため、硬化反応を十分に行い製品化されており耐溶剤性が強い。触媒硬化型の例としては、ベンジルジメチルアミン等の第３アミン、２メチルイミダゾ−ル等のイミダゾ−ル類、ルイス酸やオニウム塩などのカチオン触媒がある。重付加型の例としては、ポリアミン、フェノ−ルノボラックやレゾ−ル、ポリメルカプタン、酸無水物などである。
【００１５】
【作用】
本発明によれば、剥離を要する接着剤部に剥離用組成物を形成し暫時接触させる。この時多孔質体微粉を含有しているので、剥離用組成物は揺変（チキソトロピ−）性を有し、剥離を要する接着剤部に剥離用組成物を形成する時は液状で比較的低粘度のため形成が容易であるが、形成後の静置により増粘剤として作用し必要部外への流出を防ぎ補修が必要な部分のみへの形成を容易にする。また多孔質体微粉の空隙部に充填されていた溶剤は、接触過程で接着剤との界面にしみだし剥離を要する接着剤部を常時湿潤して、接着剤と任意の時間接触することができる。この時、組成物中に沸点が高いケトン化合物を含むので揮発しにくい。また剥離用組成物中には、接着剤を分解または溶解、膨潤する性質が強いケトン化合物を含有しているので、剥離可能な状態にすることができる。剥離用組成物中の溶剤は有機溶剤のみなので、補修部および／またはその周辺部の接続信頼性を保持することが可能であり、剥離液中に酸やハロゲン系溶剤を含有しないので、特にこの効果が顕著である。
【００１６】
【実施例】
以下、本発明を実施例により具体的に説明する。
実施例１〜３
（１）剥離用組成物の作成
アセトニルアセトンにアエロジル１３０（高純度シリカ、粒径約１６ｍμ、ＢＥＴ法比表面積１３０ｍ^２／ｇ、１３０と略）の配合比（重量比で、１部…実施例１、５部…実施例２、１０部…実施例３）を変えて、乳鉢で練り添加した。実施例１〜３の粘度（ＪＩＳＫ６８３３）およびチキソトロピックインデックス（ＴＩ）は、２５０ｃｐｓ，１．３（実施例１）、８００ｃｐｓ，２．０（実施例２）、１５００ｃｐｓ，３．５（実施例１）であった。
（２）接続体
ＩＴＯ回路端子を有するガラス基板と、接続幅が１０ｍｍのＦＰＣ回路基板（いずれも回路幅５０μｍ，回路間隔５０μｍ）３枚を間隔０．５ｍｍで、異方導電性接着フィルム（イミダゾ−ル系の触媒型硬化剤含有のエポキシ系接着剤が主成分、日立化成工業株式会社製商品名アニソルムＡＣ−７０７３、厚み25μｍ）を用いて、１７０℃−２０ｋｇ／ｃｍ^２−２０秒で導電接続した。本接続条件により接着剤は硬化し十分な接続信頼性が得られることを確認した。
（３）剥離
上記（２）の接続体の中央のＦＰＣ回路基板のみを、機械的に静かに剥がした。このガラス基板及びＦＰＣ回路基板の剥離面には接続により硬化した接着剤が残存した。この剥離面上に（１）の剥離用組成物をテフロン製のスパチュラにより厚さ約２〜３ｍｍとなるように形成した。この時実施例１〜３の番号が後になるほど粘度が高くペ−スト状に近い状態であり、形成が容易であった。その状態で３０分放置した後、綿棒でこすり接着剤及び剥離用組成物を除去し、さらにアセトンを含浸した綿棒で清浄化した。同様にＦＰＣ回路も清浄化した。両者とも剥離用組成物の他部への浸透がなく、必要部のみの剥離が可能であった。
（４）再接続
前項でえた清浄化したガラス基板及びＦＰＣを用いて、前記と同様にＡＣ−７０７３により再接続した。再接続を行ったＦＰＣ回路部の接続抵抗及び、これと隣接するＦＰＣ回路の接続抵抗と、接着剤の除去を実施する前の接続抵抗との差は、±０．５Ω以内で、各実施例とも接続抵抗の上昇は見られなかった。また実施例１〜３に用いたＦＰＣは、銅箔とポリイミド基材の接着剤として、やはりエポキシ系接着剤が主成分（硬化剤はヘキサヒドロ無水フタル酸／ジシアンジアミド系）であったが、この接着剤の劣化は見られなかった。この理由として、ＦＰＣ接着剤は重付加型であるのに対し、異方導電性接着フィルムの接着剤は開環重合を開始させる触媒硬化型であり、硬化物の構造が異なるために剥離性に差を生じたものと考えられる。
【００１７】
比較例１
実施例１〜３と同様であるが、剥離用組成物の多孔質体微粉を含まない場合である。この場合、剥離用組成物を形成放置した際に隣接するＦＰＣ回路部にまで流れてしまい、隣接したＦＰＣの接続抵抗が上昇してしまった。
【００１８】
実施例４〜６
実施例２と同様であるが、剥離用組成物中の多孔質体微粉の種類をかえた。実施例４においては、スメクタイトＳＡＮ（合成スメクタイト、ＢＥＴ法比表面積７５０ｍ^２／ｇ、ＳＡＮと略）を用い、実施例５においてはチタニウムオキサイドＰ２５（気相法でえた高純度超微粒子状酸化チタン、粒径約２０ｍμ、ＢＥＴ法比表面積５０ｍ^２／ｇ、Ｐ２５と略）を用いた。実施例６においてはフェノ−ル樹脂の架橋フオ−ム（吸油量２５、ＰＨＦと略）をペレタイザにより粒径およそ１ｍｍ角以下になるよう微粉化して用いた。各実施例とも剥離用組成物が揺変性を有しているので形成が容易であり、形成後の静置により増粘して必要部外への流出を防ぎ、補修が必要な部分のみへの形成が容易であった。以上の様に実施例４〜６においては、剥離用組成物の他部への浸透がなく必要部のみの剥離が可能であった。また再接続部の接続抵抗の上昇は見られず良好な再接続が可能であった。
【００１９】
参考例１〜３
実施例２と同様であるが、剥離用組成物の種類と組成をかえた。すなわち新しくジアセトンアルコ−ル、ジイソブチルケトン、イソホロンを用いた。各実施例とも剥離用組成物の他部への浸透がなく、必要部のみの剥離が可能であった。また再接続部の接続抵抗の上昇は見られず良好な再接続が可能であった。
実施例７〜８
実施例２および５の剥離用組成物を用いて、接続体の構成を変えた。すなわち、半導体チップ（３×１０ｍｍ，高さ０．５ｍｍ，主面の４辺周囲にバンプとよばれる１００μｍ角、高さ２０μｍの突起した金電極が存在）のバンプ配置と対応した接続端子を有する厚み１ｍｍのガラスエポキシ基板（回路は銅箔で厚み１８μｍ、接着剤は、エポキシ樹脂が主成分で硬化剤はジアミノジフェニルメタン／イミダゾ−ル系）を用意した。実施例１と同様に、異方導電性接着フィルム（イミダゾ−ル系アニオン重合触媒硬化剤含有のエポキシ系接着剤が主成分、日立化成工業株式会社製商品名アニソルムＡＣ−８２０１、厚み３０μｍ）を用いて、１７０℃−２０ｋｇ／ｃｍ^２−２０秒で導電接続した。本接続条件により接着剤は硬化し十分な接続信頼性が得られることを確認した。上記に続いて接続体を熱盤上で１８０℃に加熱しながら、剪断力を加えながら静かにはがした。この剥離面に実施例１と同様に剥離用組成物を形成した。２０分放置後、テフロンピンセットを用いて、除去、清浄化、および再接続を行なった。両実施例共に剥離用組成物の他部への浸透がなく、必要部のみの接着剤除去が可能であった。また再接続後の接続抵抗は良好であり、信頼性に優れていた。
【００２０】
実施例９〜１０
実施例７〜８と同様であるが、半導体チップを強制的に剥離せずに、接続部周辺の接着剤はみ出し部に剥離用組成物を形成し、２４時間放置後に剥離したところ、簡単に剥離可能であった。以下実施例７〜８と同様な評価を実施したが、良好な再接続が可能であった。以上の実施例７〜１０においても、ガラスエポキシ基板の接着剤の劣化は目視観察で認められなかった。異方導電性接着フィルムとガラスエポキシ基板との硬化物の構造が異なるためと考えられる。
【００２１】
実施例１１〜１５
（１）剥離用組成物の作成
アセトニルアセトン（ＡＡ）／Ｎ−メチルピロリドン（ＮＭＰ）／アエロジル（ＡＥ）１３０（高純度シリカ、粒径約１６ｍμ、ＢＥＴ法比表面積１３０ｍ^２／ｇ、１３０と略）の配合比を表１のように変えて、乳鉢で練り添加した。これらの粘度（ＪＩＳＫ６８３３）およびチキソトロピックインデックス（ＴＩ）は、実施例１１（１０００ｃｐｓ，ＴＩ２．１）、実施例１２（２５０、１．３）、実施例１３（７００、２．１）、実施例１４（１５００、３．５）、実施例１５（５００、１．９）であった。
（２）接続体
ＩＴＯ回路端子を有するガラス基板と、接続幅が１０ｍｍのＦＰＣ回路基板（いずれも回路幅５０μｍ，回路間隔５０μｍ）３枚を間隔０．５ｍｍで、異方導電性接着フィルム（イミダゾ−ル系の触媒型硬化剤含有のエポキシ系接着剤が主成分、日立化成工業株式会社製商品名アニソルムＡＣ−７０７３、厚み25μｍ）を用いて、１７０℃−２０ｋｇ／ｃｍ^２ −２０秒で導電接続した。本接続条件により接着剤は硬化し十分な接続信頼性が得られることを確認した。
（３）剥離
上記（２）の接続体の中央のＦＰＣ回路基板のみを、機械的に静かに剥がした。このガラス基板及びＦＰＣ回路基板の剥離面には接続により硬化した接着剤が残存した。この剥離面上に（１）の剥離用組成物をテフロン製のスパチュラにより厚さ約２〜３ｍｍとなるように形成した。その状態で３０分放置した後、綿棒でこすり接着剤及び剥離用組成物を除去し、さらにアセトンを含浸した綿棒で清浄化した。同様にＦＰＣ回路も清浄化した。両者とも剥離用組成物の他部への浸透がなく、必要部のみの剥離が可能であった。
（４）再接続
前項でえた清浄化したガラス基板及びＦＰＣを用いて、前記と同様にＡＣ−７０７３により再接続した。再接続を行ったＦＰＣ回路部の接続抵抗及び、これと隣接するＦＰＣ回路の接続抵抗と、接着剤の除去を実施する前の接続抵抗との差は、±０．５Ω以内で、各実施例とも接続抵抗の上昇は見られなかった。また実施例１１〜１５に用いたＦＰＣは、銅箔とポリイミド基材の接着剤として、やはりエポキシ系接着剤が主成分（硬化剤はヘキサヒドロ無水フタル酸／ジシアンジアミド系）であったが、この接着剤の劣化は見られなかった。この理由として、ＦＰＣ接着剤は重付加型であるのに対し、異方導電性接着フィルムの接着剤は開環重合を開始させる触媒硬化型であり、硬化物の構造が異なるために剥離性に差を生じたものと考えられる。
【００２２】
実施例１６〜１７、参考例４〜６
実施例１１〜１５と同様であるが、剥離用組成物の種類と組成をかえた。すなわち新しくジアセトンアルコ−ル（ＤＡ）、ジイソブチルケトン（ＤＢ）、ホルムアミド（ＨＡ），スメクタイトＳＡＮ（合成スメクタイト、ＢＥＴ法比表面積７５０ｍ^２／ｇ，ＳＡＮ）である。各実施例とも剥離用組成物が揺変性を有しているので形成が容易であり、形成後の静置により増粘して必要部外への流出を防ぎ補修が必要な部分のみへの形成が容易であった。また再接続部の接続抵抗の上昇は見られず良好な再接続が可能であった。
【００２３】
【表１】

【００２４】
実施例１８
実施例１３の剥離用組成物を用いて、接続体の構成を変えた。すなわち、半導体チップ（３×１０ｍｍ，高さ０．５ｍｍ，主面の４辺周囲にバンプとよばれる１００μｍ角、高さ２０μｍの突起した金電極が存在）のバンプ配置と対応した接続端子を有する厚み１ｍｍのガラスエポキシ基板（回路は銅箔で厚み１８μｍ、接着剤は、エポキシ樹脂が主成分で硬化剤はジアミノジフェニルメタン／イミダゾ−ル系）を用意した。実施例１１と同様に、異方導電性接着フィルム（イミダゾ−ル系アニオン重合触媒硬化剤含有のエポキシ系接着剤が主成分、日立化成工業株式会社製商品名アニソルムＡＣ−８２０１、厚み３０μｍ）を用いて、１７０℃−２０ｋｇ／ｃｍ^２−２０秒で導電接続した。本接続条件により接着剤は硬化し十分な接続信頼性が得られることを確認した。上記に続いて接続体を熱盤上で１８０℃に加熱しながら、剪断力を加えながら静かにはがした。この剥離面に実施例１と同様に剥離用組成物を形成した。２０分放置後、テフロンピンセットを用いて、除去、清浄化、および再接続を行なった。両実施例共に剥離用組成物の他部への浸透がなく、必要部のみの接着剤除去が可能であった。また再接続後の接続抵抗は良好であり、信頼性に優れていた。
【００２５】
実施例１９
実施例１８と同様であるが、半導体チップを強制的に剥離せずに、接続部周辺の接着剤はみ出し部に剥離用組成物を形成し、２４時間放置後に剥離したところ、簡単に剥離可能であった。以下実施例１８と同様な評価を実施したが、良好な再接続が可能であった。以上の実施例１８、１９においても、異方導電性接着フィルムとガラスエポキシ基板との硬化物の構造が異なるために、ガラスエポキシ基板の接着剤の劣化は目視観測では認められなかった。
【発明の効果】
本発明によれば、必要部の接着剤を効率良く剥離できるので作業性に優れる。また剥離剤の液状物は、非ハロゲン系の有機溶剤のみであり接続信頼性の維持が可能である。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a stripping composition suitable for repairing a connection portion such as a circuit or an electrode using an adhesive, and a stripping method using the same.
[0002]
[Prior art]
Along with the downsizing and thinning of electronic components, the circuits and electrodes used for these components have become denser and higher definition. For the connection of these fine circuits and the like, an adhesive method has recently been frequently used. In this case, the conductive particles are mixed in the adhesive and the electrical connection is made in the thickness direction of the adhesive by pressurization (for example, Japanese Patent Laid-Open No. 55-104007), and the conductive particles are not used at the time of connection. There is a device (for example, Japanese Patent Laid-Open No. 60-262430) in which electrical connection is made by fine unevenness of the electrode surface by pressurizing.
[0003]
In the connection with these adhesives, if the electrical connection is poor or the electronic components or circuits become defective after connection, the connection parts are peeled off, and the remaining adhesive is removed with a solvent, stripping solution, etc. The non-defective product is connected again with an adhesive. At this time, when connecting a large number of other electronic components such as an IC chip to a single electronic component having a large number of connection circuits such as a liquid crystal display panel, This affects other connection parts, and there is a problem that connection failure and reliability deteriorate.
[0004]
In recent years, adhesives used in such applications are often used with a curing type using heat, ultraviolet rays, etc. due to their excellent connection reliability. Was used while having a problem of lowering. As measures against these problems, the present inventors previously proposed an attempt to include a peeling solution in a porous sheet having a predetermined shape substantially equal to the area of the adhesive that requires repairing, and to peel it in contact with the adhesive that requires repairing. did. (Japanese Patent Laid-Open No. 3-283284)
[0005]
[Problems to be solved by the invention]
The method disclosed in Japanese Patent Laid-Open No. 3-283284 is an extremely effective peeling method for a limited area. However, since a porous sheet having a predetermined shape is formed only in a portion that needs repair, the sheet can be cut accurately. Since it is necessary to impregnate and impregnate the stripping solution, workability may be lacking. In addition, when the stripper contains an acid or a halogen-based solvent, electrolytic corrosion is likely to occur, and connection reliability is insufficient. In addition, when connecting a circuit on a glass epoxy substrate, if the surface of the adhesive that requires peeling is in the vicinity of the same adhesive material, the underlying substrate depends on the degree of the peeling solution In addition, there is a disadvantage that the adhesive of the circuit and the adhesive of the circuit and the substrate are deteriorated.
[0006]
The present invention has been made to eliminate the above-mentioned drawbacks, and proposes a stripping composition and stripping method that can efficiently strip only an adhesive that requires repair and that has excellent connection reliability. is there.
[0007]
[Means for Solving the Problems]
The present invention contains 0.5 to 50 parts by weight of a porous fine powder insoluble in this solvent for 100 parts by weight of a ketone organic solvent having two or more carbonyl groups in one molecule having a boiling point of 110 ° C. or higher. The present invention relates to a peeling composition formed by the above-mentioned method, and a peeling method in which the composition is brought into contact with an adhesive part that needs to be peeled, and removed for a while and then cleaned.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
The organic solvent used in the present invention will be described below. The organic solvent has a property of decomposing, swelling, or dissolving the adhesive, and in particular, one that can easily decompose, swell, or dissolve the cured adhesive. Therefore, as the essential solvent in the present invention , a ketone organic solvent having two or more carbonyl groups in one molecule having a boiling point (760 mmHg) of 110 ° C. or higher is preferable. Such solvents are shown in, for example, Kodansha Co., Ltd., Solvent Handbook, 7th printing, pages 632 to 756, and these can be applied. In the present invention, as described above, it is essential to use a ketone organic solvent having a boiling point (760 mmHg) of 110 ° C. or higher. However, an organic solvent having a boiling point of 100 ° C. or lower may be appropriately blended if desired.
[0009]
To illustrate this solvent is A Seto acetonylacetone (191 ° C.). Those having two or more carbonyl groups in one molecule are particularly preferred because they are easy to decompose or swell the cured adhesive. The boiling point of 110 ° C. or higher is applicable from the viewpoint of suppressing volatility, preferably 120 ° C. or higher, and more preferably 140 ° C. or higher.
[0010]
It is necessary for the solvent in the stripping solution to be a non-halogen organic solvent that does not contain an acid or a halogen-based solvent in order to maintain connection reliability. The lower the viscosity of the solvent, the better the permeability to the adhesive to be peeled. Further, the SP value is preferably 8 or more, more preferably 10 or more because the adhesive has a large erosion effect. The porous fine powder used in the present invention has a large number of small voids inside or on the surface, and is required to be insoluble in the solvent of the stripping composition. In order to form the peeling composition only in a portion that needs repair, the pore diameter of the gap is preferably 100 μm or less, more preferably 40 μm or less, from the point of fineness of the applied circuits. In the present invention, the BET specific surface area (ASTMD-3037-73) is preferably 1 m ² / g or more, and more preferably 10 m ² / g or more as an index indicating the degree of voids.
[0011]
In addition, a porous material having an oil absorption (JIS K5101) of 20 or more can be preferably applied. If the porous fine powder used in the present invention is soluble in a solvent, it is not preferable because the thixotropic property of the peeling composition and the retention of the solvent are lowered, but these characteristics are not significantly lowered and are practically problematic. If not, there is no problem with the degree of swelling. Examples of these porous fine powders include carbonates such as calcium carbonate and magnesium, hydroxides such as aluminum hydroxide and magnesium, oxides such as zinc oxide and magnesium, silicic acid such as silica, smectite, and talc, and silicic acid. There are polymer particles such as salt, styrene and epoxy resin. In the case of polymer particles, a crosslinked product is preferable for preventing deterioration due to a solvent. A conductive material such as carbon is also preferable because it has a function of removing static electricity generated by friction in the cleaning process. These particles are preferably in the form of fine particles because thixotropic properties can be obtained even if the amount added is small, and the particle size is 10 μm or less, more preferably 1 μm or less. Further, it is also possible to apply a cross-linked polymer porous sheet or water-absorbing resin which is pulverized by pulverization or the like. In this case, the size of the fine powder can be applied to a relatively large size of several mm or less, preferably several hundred μm or less, so that it can be easily dispersed in the stripping composition, and the amount of solvent retained is large. This is preferable. It is also possible to use a mixture of the pulverized product and the particulate material.
[0012]
The peeling composition according to the present invention is obtained by adjusting the composition comprising the above to a liquid state. The reason for making it liquid is that it can be easily formed only in the portion that needs repair. At this time, the viscosity (JIS K6833) of the composition is preferably 100 cps or more, and more preferably 800 cps or more. The upper limit of the viscosity can be applied in a wide range up to a paste of about 100,000 cps. Further, the thixotropic index by the same method is preferably 1.2 or more, and more preferably 1.5 or more. When the viscosity is low, the adhesive has excellent penetrability. When the thixotropic index is large, precise formability in details is improved. For these reasons, the added amount of the porous fine powder can be 0.5 to 50 parts by weight, more preferably 1 to 20 parts by weight, with respect to 100 parts by weight of the solvent. In the stripping composition, for example, polymers as thickeners soluble in the solvent used, surfactants that enhance the permeability of the solvent to the adhesive to be stripped, and coloring to clearly indicate the formation area Materials, etc. can be used as needed.
[0013]
A peeling method using the above-described peeling composition will be described. First, the joint portions of the connection portions that require repair are peeled off as necessary to expose the adhesive surface that needs to be peeled off. At this time, for example, if the heating is performed at a temperature higher than the glass transition point of the adhesive, the peeling is easy. If the peeling composition can easily enter the joint, such as when the repair area is small, this step can be omitted. Next, a stripping composition is formed on the exposed adhesive surface that requires stripping and brought into contact for a while. As the forming means, since the peeling composition is liquid, for example, a brush, a dispenser, a silk screen or the like can be selected as appropriate. At this time, in order to prevent an adverse effect on the peripheral portion, a portion not to be removed may be protected by a masking tape or the like. The contact time is determined by the time for decomposing or dissolving the adhesive. If heating is performed to such an extent that volatilization of the high-boiling solvent can be suppressed at this time, it is easier to decompose or dissolve the adhesive, which is effective for shortening the working time. After this, the adhesive is removed and cleaned by wiping the surface of the release composition with cloth, paper, cotton swabs, etc., or wiping them with a solvent such as acetone or alcohol. To do.
[0014]
In the adhesive to which the present invention is applied, the curing agent is preferably a catalyst curing type, for example, an epoxy resin as a main component. That is, since the adhesive for circuit connection is required to be cured for a short time, a catalyst curing type that starts ring-opening polymerization is used. On the other hand, a polyaddition type is often used as a substrate or an adhesive between a substrate and a circuit, and the structure of these cured products is different, so that a difference in solvent resistance occurs. In general, the polyaddition type, compared to the catalyst curing type, has insufficient mechanical properties unless it is highly reticulated. Therefore, the polyaddition type is sufficiently commercialized and has high solvent resistance. Examples of the catalyst curing type include tertiary amines such as benzyldimethylamine, imidazoles such as 2-methylimidazole, and cationic catalysts such as Lewis acids and onium salts. Examples of the polyaddition type include polyamines, phenol novolacs, resoles, polymercaptans, acid anhydrides, and the like.
[0015]
[Action]
According to the present invention, a peeling composition is formed on an adhesive part that requires peeling and is brought into contact for a while. At this time, since the porous fine powder is contained, the stripping composition has thixotropic properties, and when the stripping composition is formed on the adhesive part that requires stripping, it is liquid and relatively low. Although it is easy to form due to its viscosity, it acts as a thickener by standing after formation, preventing outflow to the outside of the necessary part and facilitating formation only on the part requiring repair. In addition, the solvent filled in the voids of the porous fine powder can always come into contact with the adhesive for an arbitrary period of time by moistening the adhesive part that oozes out at the interface with the adhesive in the contact process and requires peeling. At this time, since the composition contains a ketone compound having a high boiling point, it is difficult to volatilize. Moreover, since the peeling composition contains a ketone compound having a strong property of decomposing, dissolving, or swelling the adhesive, it can be made in a peelable state. Since the solvent in the stripping composition is only an organic solvent, it is possible to maintain the connection reliability of the repaired part and / or its peripheral part, and the stripping solution does not contain an acid or halogen-based solvent. The effect is remarkable.
[0016]
【Example】
Hereinafter, the present invention will be specifically described by way of examples.
Examples 1-3
(1) Preparation of stripping composition Acetonylacetone and Aerosil 130 (high purity silica, particle size of about 16 mμ, BET specific surface area of 130 m ² / g, abbreviated as 130) (weight ratio: 1 part) Example 1, 5 parts, Example 2, 10 parts, Example 3) were changed and kneaded in a mortar. The viscosities (JIS K6833) and thixotropic index (TI) of Examples 1 to 3 are 250 cps, 1.3 (Example 1), 800 cps, 2.0 (Example 2), 1500 cps, 3.5 (Example) 1).
(2) Connection body An anisotropic conductive adhesive film (Imidazo) with a glass substrate having ITO circuit terminals and three FPC circuit boards with connection widths of 10 mm (both circuit width 50 μm, circuit interval 50 μm) at intervals of 0.5 mm. -Conductive at 170 ° C.-20 kg / cm ² -20 seconds using an epoxy-based adhesive containing a catalyst-type curing agent as a main component and trade name Anisolum AC-7073, thickness 25 μm manufactured by Hitachi Chemical Co., Ltd. Connected. It was confirmed that the adhesive was cured by this connection condition and sufficient connection reliability was obtained.
(3) Peeling Only the central FPC circuit board of the connection body of (2) was peeled mechanically and gently. The adhesive cured by the connection remained on the peeled surfaces of the glass substrate and the FPC circuit board. On this peeling surface, the peeling composition of (1) was formed with a Teflon spatula so as to have a thickness of about 2 to 3 mm. At this time, as the numbers of Examples 1 to 3 were later, the viscosity was higher and the state was closer to paste, and the formation was easier. After leaving in that state for 30 minutes, the rubbing adhesive and the peeling composition were removed with a cotton swab and further cleaned with a cotton swab impregnated with acetone. Similarly, the FPC circuit was also cleaned. In both cases, there was no penetration into the other part of the stripping composition, and only the necessary part could be stripped.
(4) Reconnection Using the cleaned glass substrate and FPC obtained in the previous section, reconnection was performed using AC-7073 as described above. The difference between the connection resistance of the reconnected FPC circuit section, the connection resistance of the adjacent FPC circuit, and the connection resistance before carrying out the removal of the adhesive is within ± 0.5Ω. In both cases, there was no increase in connection resistance. Further, the FPC used in Examples 1 to 3 was mainly composed of an epoxy adhesive as an adhesive between the copper foil and the polyimide base material (the curing agent was hexahydrophthalic anhydride / dicyandiamide). The agent was not deteriorated. The reason for this is that while the FPC adhesive is a polyaddition type, the adhesive for the anisotropic conductive adhesive film is a catalyst-curing type that initiates ring-opening polymerization, and the structure of the cured product is different, making it peelable. It is considered that a difference has occurred.
[0017]
Comparative Example 1
Although it is the same as that of Examples 1-3, it is a case where the porous body fine powder of the composition for peeling is not included. In this case, when the peeling composition was left as it was, it flowed to the adjacent FPC circuit portion, and the connection resistance of the adjacent FPC increased.
[0018]
Examples 4-6
Although it is the same as that of Example 2, the kind of porous body fine powder in the composition for peeling was changed. In Example 4, smectite SAN (synthetic smectite, BET specific surface area 750 m ² / g, abbreviated as SAN) was used, and in Example 5, titanium oxide P25 (high purity ultrafine titanium oxide obtained by vapor phase method, A particle size of about 20 mμ, a BET specific surface area of 50 m ² / g, abbreviated as P25) was used. In Example 6, a phenolic resin foam (oil absorption 25, abbreviated as PHF) was finely pulverized with a pelletizer so that the particle size was about 1 mm square or less. In each example, the stripping composition has thixotropic properties, so it is easy to form, thickens by standing after formation to prevent outflow to the outside of the necessary part, and only to the part that needs repair. Formation was easy. As described above, in Examples 4 to 6, there was no permeation to the other part of the stripping composition, and only the necessary part could be peeled off. Further, no increase in connection resistance at the reconnection portion was observed, and good reconnection was possible.
[0019]
Reference Examples 1-3
Although it is the same as that of Example 2, the kind and composition of peeling composition were changed. That is, diacetone alcohol, diisobutyl ketone, and isophorone were newly used. In each Example, there was no penetration into the other part of the stripping composition, and only the necessary part could be stripped. Further, no increase in connection resistance at the reconnection portion was observed, and good reconnection was possible.
Examples 7-8
Using the stripping compositions of Examples 2 and 5, the structure of the connection body was changed. That is, it has connection terminals corresponding to the bump arrangement of a semiconductor chip (3 × 10 mm, height 0.5 mm, 100 μm square called bumps around the four sides of the main surface, and 20 μm high protruding gold electrodes). A glass epoxy substrate having a thickness of 1 mm (circuit is a copper foil and thickness is 18 μm, an adhesive is mainly an epoxy resin and a curing agent is diaminodiphenylmethane / imidazole system) was prepared. In the same manner as in Example 1, an anisotropic conductive adhesive film (an imidazole-based anionic polymerization catalyst curing agent-containing epoxy-based adhesive as a main component, trade name Anisolum AC-8201, manufactured by Hitachi Chemical Co., Ltd., thickness 30 μm) is used. The conductive connection was made at 170 ° C.-20 kg / cm ² -20 seconds. It was confirmed that the adhesive was cured by this connection condition and sufficient connection reliability was obtained. Following the above, the connection body was gently peeled off while applying a shearing force while heating it to 180 ° C. on a hot platen. A release composition was formed on the release surface in the same manner as in Example 1. After leaving for 20 minutes, removal, cleaning, and reconnection were performed using Teflon tweezers. In both examples, there was no penetration into the other part of the stripping composition, and only the necessary part of the adhesive could be removed. Further, the connection resistance after reconnection was good and the reliability was excellent.
[0020]
Examples 9-10
Although it is the same as Examples 7-8 , without peeling a semiconductor chip compulsorily, the composition for peeling was formed in the adhesive protrusion of a connection part periphery, and when it peeled after leaving for 24 hours, it peels easily It was possible. The same evaluation as in Examples 7 to 8 was performed below, but good reconnection was possible. Also in the above Examples 7-10 , deterioration of the adhesive agent of the glass epoxy board | substrate was not recognized by visual observation. This is probably because the structure of the cured product of the anisotropic conductive adhesive film and the glass epoxy substrate is different.
[0021]
Examples 11-15
(1) Preparation of stripping composition Acetonylacetone (AA) / N-methylpyrrolidone (NMP) / Aerosil (AE) 130 (high purity silica, particle size of about 16 mμ, BET specific surface area 130 m ² / g, 130 The mixing ratio of (omitted) was changed as shown in Table 1, and kneaded and added in a mortar. These viscosities (JIS K6833) and thixotropic index (TI) are shown in Example 11 (1000 cps, TI2.1), Example 12 (250, 1.3), Example 13 (700, 2.1), Example 14 (1500, 3.5), Example 15 (500, 1.9).
(2) Connection body An anisotropic conductive adhesive film (Imidazo) with a glass substrate having ITO circuit terminals and three FPC circuit boards with connection widths of 10 mm (both circuit width 50 μm, circuit interval 50 μm) at intervals of 0.5 mm. -Conductive at 170 ° C.-20 kg / cm ² -20 seconds using an epoxy-based adhesive containing a catalyst-type curing agent as a main component and trade name Anisolum AC-7073, thickness 25 μm manufactured by Hitachi Chemical Co., Ltd. Connected. It was confirmed that the adhesive was cured by this connection condition and sufficient connection reliability was obtained.
(3) Peeling Only the central FPC circuit board of the connection body of (2) was peeled mechanically and gently. The adhesive cured by the connection remained on the peeled surfaces of the glass substrate and the FPC circuit board. On this peeling surface, the peeling composition of (1) was formed with a Teflon spatula so as to have a thickness of about 2 to 3 mm. After leaving in that state for 30 minutes, the rubbing adhesive and the peeling composition were removed with a cotton swab and further cleaned with a cotton swab impregnated with acetone. Similarly, the FPC circuit was also cleaned. In both cases, there was no penetration into the other part of the stripping composition, and only the necessary part could be stripped.
(4) Reconnection Using the cleaned glass substrate and FPC obtained in the previous section, reconnection was performed using AC-7073 as described above. The difference between the connection resistance of the reconnected FPC circuit section, the connection resistance of the adjacent FPC circuit, and the connection resistance before carrying out the removal of the adhesive is within ± 0.5Ω. In both cases, there was no increase in connection resistance. In addition, the FPC used in Examples 11 to 15 was mainly composed of an epoxy adhesive as an adhesive between the copper foil and the polyimide base (the curing agent was hexahydrophthalic anhydride / dicyandiamide). The agent was not deteriorated. The reason for this is that while the FPC adhesive is a polyaddition type, the adhesive for the anisotropic conductive adhesive film is a catalyst-curing type that initiates ring-opening polymerization, and the structure of the cured product is different, making it peelable. It is considered that a difference has occurred.
[0022]
Examples 16-17, Reference Examples 4-6
Although it is the same as that of Examples 11-15 , the kind and composition of peeling composition were changed. That is, they are newly diacetone alcohol (DA), diisobutyl ketone (DB), formamide (HA), smectite SAN (synthetic smectite, BET specific surface area 750 m ² / g, SAN). In each example, the release composition has thixotropic properties, so it is easy to form, and after forming, it is thickened by standing to prevent it from flowing out of the necessary part and forming only on the part that needs repair. Was easy. Further, no increase in connection resistance at the reconnection portion was observed, and good reconnection was possible.
[0023]
[Table 1]

[0024]
Example 18
Using the peeling composition of Example 13 , the structure of the connection body was changed. That is, it has connection terminals corresponding to the bump arrangement of a semiconductor chip (3 × 10 mm, height 0.5 mm, 100 μm square called bumps around the four sides of the main surface, and 20 μm high protruding gold electrodes). A glass epoxy substrate having a thickness of 1 mm (a circuit is a copper foil with a thickness of 18 μm, an adhesive is mainly composed of an epoxy resin and a curing agent is a diaminodiphenylmethane / imidazole system) was prepared. As in Example 11 , an anisotropic conductive adhesive film (an imidazole-based anionic polymerization catalyst curing agent-containing epoxy-based adhesive as a main component, trade name Anisolm AC-8201, manufactured by Hitachi Chemical Co., Ltd., thickness 30 μm) The conductive connection was made at 170 ° C.-20 kg / cm ² -20 seconds. It was confirmed that the adhesive was cured by this connection condition and sufficient connection reliability was obtained. Following the above, the connection body was gently peeled off while applying a shearing force while heating it to 180 ° C. on a hot platen. A release composition was formed on the release surface in the same manner as in Example 1. After leaving for 20 minutes, removal, cleaning, and reconnection were performed using Teflon tweezers. In both examples, there was no penetration into the other part of the stripping composition, and only the necessary part of the adhesive could be removed. Further, the connection resistance after reconnection was good and the reliability was excellent.
[0025]
Example 19
As in Example 18 , but without forcibly peeling the semiconductor chip, a peeling composition was formed on the protruding portion of the adhesive around the connection part, and after leaving it for 24 hours, it was peeled off. there were. The same evaluation as in Example 18 was performed below, but good reconnection was possible. Also in Examples 18 and 19 , the deterioration of the adhesive of the glass epoxy substrate was not observed by visual observation because the structures of the cured products of the anisotropic conductive adhesive film and the glass epoxy substrate were different.
【The invention's effect】
According to the present invention, it is excellent in workability because the adhesive in the necessary part can be efficiently peeled off. Further, the liquid release agent is only a non-halogen organic solvent, and connection reliability can be maintained.

Claims

A circuit comprising 0.5 to 50 parts by weight of a porous fine powder insoluble in a solvent with respect to 100 parts by weight of a ketone organic solvent having two or more carbonyl groups in one molecule having a boiling point of 110 ° C. or higher. A composition for peeling an adhesive at a connection portion.

The adhesive peeling composition according to claim 1, wherein the ketone organic solvent having two or more carbonyl groups in one molecule is acetonyl acetone.

A circuit connection part peeling method comprising contacting the composition according to claim 1 or 2 with a circuit connection part that requires peeling, and wiping and cleaning after contact for a while.

The adhesive of the circuit connection portion is state, and are not mainly composed of catalyst-setting epoxy resin, peeling method of circuit connector according to claim 3, wherein the adhesive substrate is a polyaddition type.